Process chocolate biscuits into fine breadcrumbs.

Melt butter and combine with biscuit crumbs.

Press the crumb mixture into the base and sides of a 21cm springform tin.

Refrigerate the crust for 30 minutes until firm.

Beat cream cheese, sugar, and lemon juice until smooth and creamy.

Dissolve gelatin in water over simmering water and cool for 5 minutes.

Whip heavy cream until soft peaks form.

Fold whipped cream and gelatin mixture into the cheese mixture.

Drain black cherries, reserving syrup.

Spoon one-third of the cheesecake mixture into the tin.

Top with half of the cherries.

Repeat layering, ending with the cheese mixture.

Refrigerate for 3 hours or overnight until set.

For the topping, blend cornflour and sugar with reserved cherry syrup in a saucepan.

Stir over heat until the mixture boils and thickens.

Stir in dark rum and cool for 10 minutes.

Spread the topping over the cheesecake.

Refrigerate until the topping is set.